I'm generating some fairly basic SVG files and will want to convert them to PNG format. Each SVG file will be used to create a number of PNG files of different sizes (it's only a size change; aspect ratio, colours, etc. all remaining the same). I'd also like the solution to be as portable as possible (at least working on *nix and MSWin platforms). I've included my investigations so far, my questions are at the end.

Here's the test SVG file, test.svg, that I've been playing with and referenced in various examples below:

<Reveal this spoiler or all in this thread>

I had the ImageMagick® convert utility available, so I tried that first. This seemed to work fine; I tested at two reduced sizes: 

$ convert test.svg -resize 16x16 test016.png
$ convert test.svg -resize 32x32 test032.png

[download]

However, when I looked into installing the Image::Magick module for use in my scripts, I was amazed to find only failures (UNKNOWN: 1276; FAIL: 412) in the "CPAN Testers Matrix: PerlMagick 6.89-1". I followed the links to the previous five releases, thinking maybe there was some problem with just 6.89-1; unfortunately, all were exactly the same except for 6.86 which had just one PASS amongst hundreds of failures. I don't know if that's some sort of reporting error. I chose not to follow that path any further.

I had previously, successfully installed GD, so I decided to look into that further. I browsed the GD::Convert, GD::SVG and SVG modules. While this looked like it might work (after a fashion), it didn't seem particularly straightforward and even the documentation says:

"GD::SVG may provide a short-term solution while scripts are re-written to enable more direct output of SVG."

There were also too many caveats for my liking, so I abandoned this avenue also.

SVG has a small section on converting to PNG. It mentions Image::Magick and also Image::LibRSVG. I hadn't heard of this other module before and decided to try it. It installed without any fuss and usage was totally uncomplicated: 

$ perl -wMstrict -MImage::LibRSVG -e 'Image::LibRSVG::->new()->convert
+AtSize("test.svg", "test016.png", 16, 16)'
$ perl -wMstrict -MImage::LibRSVG -e 'Image::LibRSVG::->new()->convert
+AtSize("test.svg", "test032.png", 32, 32)'

[download]

Not only that, but it produced PNG files that were substantially smaller than those produced by convert (without any noticable degradation of image quality; in fact, the 16x16 one looked a little crisper). I had renamed the files I produced earlier (*.png to *_via_convert.png), here's a size comparison: 

-rw-r--r-- 1 ken staff   678 Apr 23 13:03 test.svg
-rw-r--r-- 1 ken staff   124 Apr 23 14:01 test016.png
-rw-r--r-- 1 ken staff   316 Apr 23 13:10 test016_via_convert.png
-rw-r--r-- 1 ken staff   186 Apr 23 13:57 test032.png
-rw-r--r-- 1 ken staff   415 Apr 23 13:11 test032_via_convert.png

[download]

My only concerns with Image::LibRSVG are its age (no update in 11 years) and no successful builds on MSWin. The age may not be a huge issue: SVG has been stable for many years and, as an interface to the librsvg library, it may rely on that library being current, especially if its API hasn't changed. I randomly checked many failures on "CPAN Testers Matrix: Image-LibRSVG 0.07": all (going back to Perl 5.10) were UNKNOWNs, and all failed due to the librsvg library not being found — this may not be a problem either.

So, after all that, I have these questions:

— Ken

In reply to Image Conversion: SVG to PNG by kcott

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.